Primary key/ Clusters indexes on big tables in warehouse

  • Hi,

    Our fact table has 40M rows. Currently we have a identity column as PK, since we can't build a unique key with the columns we have in our table. We never use this column in any case, so basically the data is sorted on a way that we never use, but it was the only way to get a unique key on the table. Is it a good idea to have this kind of PK for a big table? I figure out it was kinda useful for reorg/defrag purpose….

    Any advise will be helpful.

    Thanks for your help

    Rem

  • You said FACT table therefore you are talking about a Data Warehouse environment.

    You do not use a natural PK on Data Warehouse, by using surrogate keys you are doing the right thing.

    _____________________________________
    Pablo (Paul) Berzukov

    Author of Understanding Database Administration available at Amazon and other bookstores.

    Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.
  • The surrogate keys will help to keep every rows unique, right? This can be done with the current identity column I have in place. Therefore, I can drop all constraint attach to it, this is correct?

    Thanks,

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